Death and Why?

Death is a living creature
Comes to one too many
The patient can die
The doctor can die
Sometimes in pressure
Sometimes very funny
Who lives on this treasure?
The poor can die
The wealthy can die
Off course death is so tiny
It comes without a measure
The healthy can die
The weak can die
What type of living creature
Lives endlessly
Oh! All who live can die
Then why death cannot die?